From DE 102 48 172 A1 an automatic transmission with a disk clutch is known, which comprises a servomechanism in the form of an actuating piston-cylinder arrangement with dynamic pressure compensation, arranged radially inside a disk carrier, for actuating the clutch. In addition, this automatic transmission comprises a planetary gearset with a planetary gear carrier. The servomechanism of this transmission comprises an actuating piston which, together with a correspondingly configured wall of a disk carrier of the clutch, forms a pressure chamber. When the pressure chamber is pressurized via a pressure medium delivery bore, then when the restoring force of a restoring spring has been overcome the actuating piston, is moved axially against the clutch disks.
On the side of the actuating piston, opposite the pressure chamber is arranged a pressure compensation chamber to receive a fluid by way of which the dynamic fluid pressure on the actuating piston, caused by the rotation of the clutch, is at least approximately compensated. For this, the pressure compensation chamber is filled with a lubricant admitted through a lubricant bore located in a hub of the disk carrier. In this known transmission, the pressure compensation chamber, arranged radially under the clutch disks and axially next to the actuating piston and the pressure chamber, is formed by a profiled spacer plate as an axially fixed, diaphragm plate and by a pot-shaped section of the axially displaceable actuating piston.
The supply of the lubricant to the planetary gears and the supply of the pressure compensation chamber also take place through a common inlet arranged in the area of the inside diameter of the profiled spacer plate and fed via the already mentioned inlet bore. At the radially inner lubricant inlet to the pressure compensation chamber, the lubricant flow is divided into two part-streams, one of which passes into the pressure compensation chamber while a second part-stream passes into a lubricant chamber close to the planetary gears.
From DE 103 33 431 A1 and DE 103 50 573 A1, a clutch arrangement in an automated shift transmission, is known in each case, with two axially and radially adjacent disk clutches B and E, where the inner disks of the radially inner clutch E are arranged on an inner disk carrier and the outer disks of the radially outer clutch B are arranged on an outer disk carrier. The inner disks of the radially outer clutch B and the outer disks of the radially inner clutch E are positioned on a common disk carrier with respective inner disks and outer disks of the two clutches B and E arranged axially in alternation.
Associated with each of the two disk sets is an actuating piston-cylinder arrangement, whose actuating piston is, in each case, associated with a respective pressure chamber for a fluid pressure medium to produce an actuating force, a pressure compensation chamber being provided in each case. These actuating piston-cylinder arrangements, referred to as servo-mechanisms, are arranged in such a manner that the two clutches B and E can be actuated in the same axial direction to close them.
The pressure compensation chamber of the radially outer clutch B in this arrangement has its filling zone partially at the same radial height as and an axial distance away from the pressure chamber of the associated actuating piston. In addition, this pressure compensation chamber is axially delimited in its filling zone by the inner wall of the actuating piston and by a diaphragm plate with a sealing element.
In this pressure compensation chamber, a restoring element is arranged, made as a compression spring packet and orientated axially parallel to the actuation direction, which is prestressed between the middle section of the common disk carrier and the actuating piston. Between the end of this compression spring packet on the disk carrier side and the disk carrier section is clamped a disk-shaped section of the diaphragm plate so that the diaphragm plate is pressed axially against the disk carrier.
To delimit the pressure compensation chamber axially and radially, the diaphragm plate, according to DE 103 33 431 A1, is configured and fitted in such a manner that between it and the radial disk carrier section, a flow channel is left free, which comprises an inlet opening for the coolant or lubricant loading into the pressure compensation chamber and an outlet opening in a horizontal section of the common disk carrier. The position of the inlet opening in the flow channel is chosen in the radial direction on the diaphragm plate so that it matches a predetermined overflow height into the pressure compensation chamber. This overflow height radially covers a section of the pressure space for the associated actuating piston.
Finally, from DE 103 42 897 A1, a device for actuating a clutch in a transmission is known, which consists of an actuating piston-cylinder arrangement with rotation pressure compensation, with whose actuating piston is associated a pressure chamber for a fluid pressure medium to produce the actuating force, and in which a pressure compensation chamber is provided, in which pressure medium fluid produces by virtue of centrifugal action, a compensation force on the actuating piston, whose direction is opposite to the active actuation direction of the actuating piston. The pressure compensation chamber is arranged radially outside the pressure chamber. In this device, it is additionally provided that the pressure compensation chamber is supplied with pressure medium via the pressure chamber. This. avoids separate supply lines for the pressure chamber and the pressure compensation chamber. The supply line, pressure chamber and the pressure compensation chamber are positioned as if radially in series and have no axial separation from one another. A further feature of this actuating piston-cylinder arrangement is that the pressure actuation chamber is delimited by a horizontal section of the outer disk carrier and by the actuating piston.
This known device, for correspondingly configured transmission structures, is certainly an improvement in that it saves a supply line. However it cannot, or only sometimes, be used in transmission structures such as those known from DE 103 50 573 A1 and DE 103 33 431 A1. The solutions described therein have proved their worth in practice, but still leave room for improvement. In particular, those clutch arrangements require the incorporation of a diaphragm plate or sheet. This diaphragm sheet, which delimits the pressure compensation chamber in the radial and axial direction, is a separate component which takes up structural space and has to be produced separately. To an increasing extent, however, as the design of the transmissions gets ever more compact and, at the same time more complex, it is precisely structural space that becomes very restricted. Moreover, a separate component adds to the production and assembly costs.
Against this background the purpose of the present invention is to provide a device of the type described, which consists of as few components as possible and takes up comparatively little structural space.